Report on Pavlof (United States) — October 1983

Scientific Event Alert Network Bulletin, vol. 8, no. 10 (October 1983)
Managing Editor: Lindsay McClelland.

Pavlof (United States) Large eruption column; tremor

Please cite this report as:

Global Volcanism Program, 1983. Report on Pavlof (United States). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 8:10. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198310-312030.

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Pavlof

United States

55.417°N, 161.894°W; summit elev. 2493 m

All times are local (unless otherwise noted)


Strong tremor started to appear on local seismic records on 14 November at about 1500 and by 1800 was saturating the instruments. The mayor of Sand Point, about 90 km E of Pavlof, saw glow over the volcano at 2330 that night. At 1220 the next day, an airline pilot reported an eruption column rising to about 5.5 km altitude through weather clouds that covered the summit and obscured the vent area. Twenty minutes later, the column had reached 7.5 km altitude. Tephra emission was continuing at 1300. The plume blew S and SE, and spread to about 50 km width, 50 km S of the volcano. Aircraft were diverted from the area. Tremor continued to saturate the seismic instruments through the afternoon.

Geologic Background. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.

Information Contacts: T. Miller, USGS, Anchorage; S. McNutt, LDGO.